The present invention relates to saw blades, and, more particularly, to saw blades that use a diamond shaped arbor.
A number of different power tools utilize circular saw blades to cut or grind various materials. These power tools have a motor that is selectively operable to rotate a shaft. The selective operation of the motor causes the shaft to rotate. The shafts on these power tools can come in a variety of shapes. For example, the shaft can have a circular cross section, as is typical for most power tools utilizing a circular saw blade, or can have a generally diamond shaped cross section, as is typical in worm gear drive power tools. A circular saw blade for use with these power tools has a central opening that is configured and adapted to fit on the shaft of the power tool and rotate along with the rotation of the shaft so that the power tool can perform a cutting or grinding operation.
Universal saw blades that can be used on power tools having either the circular shaft or the diamond shaped shaft have a generally diamond shaped arbor pressed into the center of the saw blade that can be selectively removed. The arbor has a generally circular central opening that enables the saw blade with the arbor to be used on power tools having a circular shaft. The arbor can be removed from a saw blade thereby leaving a central opening in the saw blade that is diamond shaped. The saw blade with the arbor removed can then be used on power tools having a generally diamond shaped shaft. The use of the diamond shaped arbor thereby enables the saw blade to be used on power tools having either a circular shaft or a diamond shaped shaft.
In making these universal blades, the saw blades begin as blanks in a soft state. A circular central opening is made in the blank along with any teeth, expansions slots, vent slots, etc. The blank is then heat treated to a desired hardness and drawn flat. At this point the universal saw blade is stress free. The saw blade then enters the diamond arbor process wherein a diamond shaped arbor that is centered around the circular central opening is removed from the saw blade. The diamond arbor is removed from a saw blade by laser cutting the arbor from the blade. Alternatively, the diamond arbor is made in a press stamping operation wherein the diamond shaped arbor is punched out of the saw blade. After the diamond arbor is removed from the saw blade, the arbor is then placed back in the saw blade by stamping the arbor into the diamond shaped opening from whence it came. The forcing of the diamond shaped arbor back into the blade creates inner stresses that retain the diamond shaped arbor in the blade but can also affect the quality of any cut made by the blade and can affect the life of the blade. The inner stresses thereby can result in decreasing a user""s satisfaction with the universal saw blade. In an attempt to remove the inner stresses, the blade may undergo further manufacturing processes, such as heating the blade up in an attempt to remove the stresses.
After the diamond arbor has been removed from and reinserted into the blade, the blade goes through further manufacturing processes. The processes may include adding specialized tips to the teeth of the saw blade, sharpening the teeth and/or tips, painting the blade, if desired, and grinding and/or polishing the blade. During all these operations, the inner stresses that retain the diamond arbor can cause the arbor to possibly dislodge from the blade thereby increasing the amount of scrap or rework that must be done to manufacture a useable universal saw blade. Additionally, by forcing the diamond arbor into the saw blade by stamping, the arbor may be off centered which would affect the quality of the cuts the blade is capable of making and will cause the blade to be out of round. Finally, the inner stresses may make it difficult for a user of the universal saw blade to remove the arbor so that the blade can be used on a power tool with a diamond shaped shaft.
Therefore, what is needed is a diamond shaped arbor that does not create inner stresses in the universal saw blade. The arbor should be easy to manufacture along with being easy to insert and remove from the universal saw blade. Finally, it would be desirable for the arbor to be self centering.
The spring loaded diamond shaped arbor of the present invention provides the above desired benefits and features. The arbor can be easily inserted into and removed from the blade. The spring feature of the diamond arbor retains the arbor within the saw blade without introducing inner stresses in the blade. Additionally, because the arbor is spring loaded, the arbor will stay in the saw blade during additional manufacturing processes.
The diamond shaped arbor for use in a saw blade of the present invention comprises a diamond shaped plate having four peripheral side walls with four corners therebetween. The four corners separate the four side walls. There is a central opening that is configured and adapted to allow the arbor to be attached to a power tool. A slot extends from the central opening through one of the side walls or corners so that the arbor can be compressed and easily inserted into and removed from a saw blade. Optionally, but preferably, the slot has opposite slot walls which are generally parallel. However, the opposite slot walls can also diverge as the slot extends from the central opening through one of the side walls or corners. Conversely, the opposite slot walls can converge as the slot extends from the central opening through one of the side walls or corners. Optionally, the slot can curve as the slot extends from the central opening through one of the side walls or corners.
In order to relieve/reduce stress cracking in a saw blade that has a generally diamond shaped central opening that receives the arbor, one or more of the corners in the opening in the saw blade may have rounded recesses, as is known in the art. In this case, the arbor may optionally have one or more complementary projections that extend outward from the corners and occupy the rounded recesses in the saw blade opening. The slot can extend through one of the corners having the projection and in such a case may also extend through the projection.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.